Structure for adjusting gain in a flash analog to digital converter

摘要

A flash analog to digital converter includes a reference ladder, consisting primarily of resistors, a plurality of comparators, each coupled to a different reference voltage on the reference ladder (the comparators compare a received voltage with a reference voltage level developed across corresponding resistor or group of resistors), and a variable power source coupled to the reference ladder for varying the reference levels generated from the ladder. The structure includes a fixed (or variable) gain driver supplying the received signal voltage to the bank of comparators. The variable power source can be an adjustable current source or an adjustable voltage source. The comparators can be single-ended comparators or differential comparators.